Rotary thermoforming (RTF) may be used to produce plastic containers and typically involves an RTF mold wheel that rotates around a horizontal axis. A plurality of molds around the periphery of the wheel include mold cavities that are aligned along radial axes perpendicular to the axis of rotation of the wheel. A warm and thin thermoplastic sheet is moved into contact with the exterior surface of the wheel and vacuum is applied to pull a portion of the thin sheet into conformity with one of the mold cavities. A mold assist tool may be moved into the mold cavity to finish form the sheet portion into an article. Cam devices may be used to drive mold tooling between a molding position to accept the thermoplastic sheet and an ejection position to eject the molded article. In general, such processes have been well known to those of ordinary skill in the art for decades.
In contrast to RTF processes, injection and blow molding processes are routinely used to produce threaded containers. But according to conventional wisdom in avoiding mold lock conditions and concomitant damage to a threaded container, the threaded container must be unscrewed from its mold in a cumbersome process, or segmented molds must be used but result in undesirable mold seams, parting lines, or flash on the threads.
General objects of the present disclosure may include providing a container that has at least one seamless external thread segment, has an enhanced sealing end surface, and/or that may be removed from a mold without having to unscrew the container from the mold or without having to use segmented molds and without concomitant mold seams on the thread segment(s).
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A molded plastic container in accordance with one aspect of the disclosure includes a bottom wall to define a closed end of the container, a side wall extending generally axially away from the bottom wall, and a neck finish terminating the side wall to define an open end of the container. The neck finish includes a finish wall having inner and outer surfaces, and at least one seamless external thread segment projecting from the outer surface of the finish wall.
A molded plastic container in accordance with another aspect of the disclosure includes a bottom wall to define a closed end of the container, a side wall extending generally axially away from the bottom wall, and a neck finish terminating the side wall to define an open end of the container. The neck finish includes a finish wall having inner and outer surfaces, and a bead extending radially inwardly from the inner surface of the finish wall, wherein the thickest section of any of the walls of the container extends through the bead.
A molded plastic container in accordance with a further aspect of the disclosure includes a bottom wall to define a closed end of the container, a side wall extending generally axially away from the bottom wall, and a neck finish terminating the side wall to define an open end of the container. The neck finish includes a finish wall having inner and outer surfaces, and a flange extending radially outwardly from the finish wall and also extending axially downwardly, the flange having a section thickness less than that of the finish wall.